Outcomes of robot-assisted radical prostatectomy in men after trans-urethral resection of the prostate: a matched-pair analysis

Prior history of transurethral resection of the prostate (TURP) can complicate Robot-assisted radical prostatectomy (RARP). Very few studies analyse the outcomes of RARP in men with a prior history of TURP. We analysed the oncological and functional outcomes of RARP in post-TURP men from our prospectively maintained database. We included the RARP data from January 2016 to January 2022. Thirty men who had RARP with a prior history of TURP were identified (Group 2). They were matched using R software and propensity score matching to 90 men with no previous TURP (Group-1). The groups were matched for age, body mass index (BMI), Gleason score, stage, PSA and D'Amico risk category in a 1:3 ratio. The two-year oncological and functional outcomes were compared. Overall, the study found no significant difference between the groups in the preoperative parameters, such as BMI, age, Gleason grade, clinical stage, PSA, prostate volume, and D'amico risk grouping. There was no difference in the estimated blood loss. The TURP group had a lower chance of having a nerve spare (p = 0.03). The median console time was longer in the TURP group (140 min (120,180) versus 168 (129,190) p = 0.058). The postoperative complications (Clavien-Dindo 3a 2% versus 6.7%) and hospital stay (median of 2 days), positive surgical margins, continence, and biochemical recurrence rates at 3, 12, and 24 months were not statistically different between the groups. In high-volume centres, the oncological and continence outcomes of RARP post-TURP are not inferior to that of men without prior TURP.

Salvage vesiculectomy for local prostate cancer recurrence: surgical technique and early post-operative outcomes

PURPOSE

Isolated recurrence in remnants of the seminal vesicles (SV) after treatment of primary prostate cancer (PCa) has become a more frequent entity with the widespread use of more sensitive next-generation imaging modalities. Salvage vesiculectomy is hypothesized to be a worthwhile management option in these patients. The primary goal of this study is to describe the surgical technique of this new treatment option. Secondary outcomes are peri- and post-operative complications and early oncological outcomes.

METHODS

Retrospective multicenter study, including 108 patients with solitary recurrence in the SV treated between January 2009 and June 2022, was performed. Patients with local recurrences outside the SVs or with metastatic disease were excluded. Both SVs were resected using a robot-assisted or an open approach. In selected cases, a concomitant lymphadenectomy was performed.

RESULTS

Overall, 31 patients (29%) reported complications, all but one grade 1 to 3 on the Clavien-Dindo Scale. A median PSA decrease of 2.07 ng/ml (IQR: 0.80-4.33, p < 0.001), translating into a median PSA reduction of 92% (IQR: 59-98%) was observed. At a median follow-up of 14 months, freedom from secondary treatment was 54%. Lymphadenectomy had a significant influence on PSA reduction (p = 0.018).

CONCLUSION

Salvage vesiculectomy for PCa recurrence limited to the SV is a safe procedure with excellent PSA response and is a potential curative treatment in a subset of patients. A concomitant lymphadenectomy can best be performed in all patients that did not underwent one at primary treatment.

Clonal hematopoiesis related TET2 loss-of-function impedes IL1β-mediated epigenetic reprogramming in hematopoietic stem and progenitor cells

Clonal hematopoiesis (CH) is defined as a single hematopoietic stem/progenitor cell (HSPC) gaining selective advantage over a broader range of HSPCs. When linked to somatic mutations in myeloid malignancy-associated genes, such as TET2-mediated clonal hematopoiesis of indeterminate potential or CHIP, it represents increased risk for hematological malignancies and cardiovascular disease. IL1β is elevated in patients with CHIP, however, its effect is not well understood. Here we show that IL1β promotes expansion of pro-inflammatory monocytes/macrophages, coinciding with a failure in the demethylation of lymphoid and erythroid lineage associated enhancers and transcription factor binding sites, in a mouse model of CHIP with hematopoietic-cell-specific deletion of Tet2. DNA-methylation is significantly lost in wild type HSPCs upon IL1β administration, which is resisted by Tet2-deficient HSPCs, and thus IL1β enhances the self-renewing ability of Tet2-deficient HSPCs by upregulating genes associated with self-renewal and by resisting demethylation of transcription factor binding sites related to terminal differentiation. Using aged mouse models and human progenitors, we demonstrate that targeting IL1 signaling could represent an early intervention strategy in preleukemic disorders. In summary, our results show that Tet2 is an important mediator of an IL1β-promoted epigenetic program to maintain the fine balance between self-renewal and lineage differentiation during hematopoiesis.

Self-removal of catheter after robot-assisted radical prostatectomy: a feasibility study

Self-removal of urinary catheter as an option after robot-assisted radical prostatectomy (RARP) has never been explored in literature. We report the feasibility and outcome of the first study of this novel concept in our hospital. We conducted a prospective audit of self-TWOC (trial without catheter) in men who underwent consecutive RARP in our centre between April 2022 and September 2022. Men who had self-TWOC filled a questionnaire about the outcomes of self-TWOC. Carbon footprint and carbon offset for each hospital TWOC avoided were calculated. Of the 129 who underwent self-TWOC, 112 filled the questionnaire and were hence included in the final analysis. Self-TWOC was successful in all the 112 (100%) men in the study. 99.1% of men were satisfied with self-TWOC at home. We managed to avoid 79.6 ± 36.72 km of travel and 77 min of travel time for every self-TWOC. This also saved 85£/patient on clinic expenses and fuel cost savings of 9.87-15.99£ per patient depending on car engine size/type. The carbon footprint calculated was 20 kg CO2 assuming average engine sized diesel/petrol cars and 10 kg CO2 for an average UK petrol hybrid car. The calculated carbon offset per patient for diesel/petrol cars: 0.32£, petrol hybrid: 0.16£. Self-TWOC for 80-160 patients will save the carbon emissions equivalent to that of a passenger on a London-New York Trans-Atlantic flight. Self-TWOC is safe, affordable and is sustainable to the environment. Widespread acceptance of this practice change will be a small, but steady step towards greener health systems across the world.

Etrolizumab as induction and maintenance therapy in patients with moderately to severely active Crohn's disease (BERGAMOT): a randomised, placebo-controlled, double-blind, phase 3 trial

BACKGROUND

Etrolizumab is a gut-targeted anti-β7 monoclonal antibody targeting α4β7 and αEβ7 integrins. We aimed to compare the safety and efficacy of two doses of etrolizumab with placebo in patients with Crohn's disease.

METHODS

BERGAMOT was a randomised, placebo-controlled, double-blind, phase 3 study done at 326 treatment centres worldwide. We included patients aged 18-80 years with moderately to severely active Crohn's disease (Crohn's Disease Activity Index [CDAI] score of 220-480, and a mean daily stool frequency score of ≥6 or a mean daily stool frequency score of >3, and a mean daily abdominal pain score of >1, as well as the presence of active inflammation on screening ileocolonoscopy) who had intolerance, inadequate response, or no response to one or more of corticosteroids, immunosuppressants, or anti-TNF therapy within the past 5 years. BERGAMOT consisted of three induction cohorts (a placebo-controlled, double-blind exploratory cohort [cohort 1]; an active treatment cohort not containing a placebo control [cohort 2]; and a placebo-controlled, double-blind pivotal cohort [cohort 3]) and one maintenance cohort. In induction cohort 3, during the 14-week induction, patients were randomly assigned (2:3:3) to receive matched placebo, 105 mg etrolizumab subcutaneously every 4 weeks (at weeks 0, 4, 8, and 12) or 210 mg etrolizumab subcutaneously (at weeks 0, 2, 4, 8, and 12), stratified by concomitant treatment with oral corticosteroids, concomitant treatment with immunosuppressants, baseline disease activity, and previous exposure to anti-TNF therapy. To preserve masking, all patients received two injections at weeks 0, 4, 8, and 12 and one injection at week 2. Week 14 etrolizumab responders from all cohorts were re-randomly assigned (1:1) to receive 105 mg etrolizumab (etrolizumab maintenance group) or placebo (placebo maintenance group) every 4 weeks for 52 weeks; patients in the induction placebo group underwent a sham re-randomisation to preserve masking. During maintenance, randomisation was stratified by CDAI remission status, concomitant treatment with oral corticosteroids, induction dose regimen, and previous exposure to anti-TNF therapy. All participants and study site personnel were masked to treatment assignment for both induction and maintenance. Co-primary induction endpoints at week 14 (placebo vs 210 mg etrolizumab) were clinical remission (mean stool frequency ≤3 and mean abdominal pain ≤1, with no worsening) and endoscopic improvement (≥50% reduction in Simple Endoscopic Score for Crohn's Disease [SES-CD]). Co-primary maintenance endpoints at week 66 (placebo vs etrolizumab) were clinical remission and endoscopic improvement. Efficacy was analysed using a modified intention-to-treat (mITT) population, defined as all randomised patients who received at least one dose of study drug (induction) and as all patients re-randomised into maintenance who received at least one dose of study drug in the maintenance phase (maintenance). Safety analyses included all patients who received at least one dose of study drug. Maintenance safety analyses include all adverse events occurring in both induction and maintenance. This trial is registered with ClinicalTrials.gov, NCT02394028, and is closed to recruitment.

FINDINGS

Between March 20, 2015, and Sept 7, 2021, 385 patients (209 [54%] male and 326 [85%] white) were randomly assigned in induction cohort 3 to receive placebo (n=97), 105 mg etrolizumab (n=143), or 210 mg etrolizumab (n=145). 487 patients had a CDAI-70 response in any of the induction cohorts and were enrolled into the maintenance cohort, of whom 434 had a response to etrolizumab and were randomly assigned to placebo (n=217) or 105 mg etrolizumab (n=217). At week 14, 48 (33%) of 145 patients in the 210 mg induction etrolizumab group versus 28 (29%) of 96 patients in the placebo induction group were in clinical remission (adjusted treatment difference 3·8% [95% CI -8·3 to 15·3]; p=0·52), and 40 (27%) versus 21 (22%) showed endoscopic improvement (5·8% [-5·4 to 17·1]; p=0·32). At week 66, a significantly higher proportion of patients receiving etrolizumab than those receiving placebo had clinical remission (76 [35%] of 217 vs 52 [24%] of 217; adjusted treatment difference 11·3% [95% CI 2·7-19·7]; p=0·0088) and endoscopic improvement (51 [24%] vs 26 [12%]; 11·5% [4·1-18·8]; p=0·0026). Similar proportions of patients reported one or more adverse events during induction (95 [66%] of 143 in the 105 mg etrolizumab group, 85 [59%] of 145 in the 210 mg etrolizumab group, and 51 [53%] of 96 in the placebo group) and maintenance (189 [87%] of 217 in the etrolizumab group and 190 [88%] of 217 in the placebo group). During induction, the most common treatment-related adverse events were injection site erythema (six [4%] of 143 in the 105 mg etrolizumab group, four [3%] of 145 in the 210 mg etrolizumab group, and none of 96 in the placebo group), and arthralgia (two [1%], one [1%], and four [4%]). In the maintenance cohort, the most common treatment-related adverse events were injection site erythema (six [3%] of 217 in the etrolizumab group vs 14 [6%] of 217 in the placebo: group), arthralgia (five [2%] vs eight [4%]), and headache (five [2%] vs seven [3%]). The most common serious adverse event was exacerbation of Crohn's disease (14 [6%] of 217 patients taking placebo and four [2%] of 217 patients taking 105 mg etrolizumab in the maintenance cohort).

INTERPRETATION

A significantly higher proportion of patients with moderately to severely active Crohn's disease achieved clinical remission and endoscopic improvement with etrolizumab than placebo during maintenance, but not during induction.

FUNDING

F Hoffmann-La Roche.

Feasibility and safety of radical prostatectomy for oligo-metastatic prostate cancer: the Testing Radical prostatectomy in men with prostate cancer and oligo-Metastases to the bone (TRoMbone) trial

OBJECTIVES

To test the feasibility of randomisation to radical prostatectomy (RP) plus pelvic lymphadenectomy in addition to standard-of-care (SOC) systemic therapy in men with newly diagnosed oligo-metastatic prostate cancer.

PATIENTS AND METHODS

A prospective, randomised, non-blinded, feasibility clinical trial with an embedded QuinteT Recruitment Intervention (QRI) to optimise recruitment was conducted in nine nationwide tertiary care centres undertaking high-volume robotic surgery. We aimed to randomise 50 men with synchronous oligo-metastatic prostate cancer within an 18-month recruitment period to SOC systemic therapy vs SOC plus RP (intervention arm). The main outcome measures were: ability to randomise patients, optimised by a QRI; EuroQoL five Dimensions five Levels (EQ-5D-5L) questionnaires to capture quality-of-life (QoL) data at baseline and 3 months post-randomisation; routine clinicopathological assessment to capture adverse events and prostate-specific antigen in both arms, plus standard perioperative parameters in the surgical arm.

RESULTS

A total of 51 men were randomised within 14 months (one was subsequently deemed ineligible), with 60-83% accrual rate in centres that recruited at least two patients. All patients completed the trial follow-up; one patient in the intervention arm subsequently did not undergo the surgical intervention and one in the SOC arm refused all therapies. The QRI positively impacted recruitment. QoL data showed similarly high functioning in both study arms. Surgery for men with oligo-metastatic prostate cancer was found to be safe and had similar impact on early functional outcomes as surgery for standard indication.

CONCLUSION

It is feasible to randomise men with synchronous oligo-metastatic prostate cancer to a surgical intervention in addition to standard systemic therapies. While surgery appeared safe with no substantial impact on QoL in this feasibility study, a large randomised controlled trial is now warranted to examine treatment effectiveness of this additional component in the multimodality management of oligo-metastatic prostate cancer.

Etrolizumab for maintenance therapy in patients with moderately to severely active ulcerative colitis (LAUREL): a randomised, placebo-controlled, double-blind, phase 3 study

BACKGROUND

Etrolizumab is a gut-targeted anti-β7 integrin monoclonal antibody. In a previous phase 2 induction study, etrolizumab significantly improved clinical remission versus placebo in patients with moderately to severely active ulcerative colitis. We aimed to evaluate the efficacy and safety of etrolizumab for maintenance of remission in patients with moderately to severely active ulcerative colitis.

METHODS

We conducted a randomised, placebo-controlled, double-blind, phase 3 study (LAUREL) across 111 treatment centres worldwide. We included adults (age 18-80 years) with moderately to severely active ulcerative colitis (Mayo Clinic total score [MCS] of 6-12 with an endoscopic subscore of ≥2, a rectal bleeding subscore of ≥1, and a stool frequency subscore of ≥1) who were naive to tumour necrosis factor inhibitors. Patients were required to have had an established diagnosis of ulcerative colitis for at least 3 months, corroborated by both clinical and endoscopic evidence, and evidence of disease extending at least 20 cm from the anal verge. During open-label induction, participants received subcutaneous etrolizumab 105 mg once every 4 weeks. Participants who had clinical response at week 10 (MCS with ≥3-point decrease and ≥30% reduction from baseline, plus ≥1-point decrease in rectal bleeding subscore or absolute rectal bleeding score of 0 or 1) proceeded into the double-blind maintenance phase and were randomly assigned (1:1) to receive subcutaneous etrolizumab 105 mg once every 4 weeks or matched placebo until week 62. Randomisation was stratified by baseline concomitant treatment with corticosteroids, treatment with immunosuppressants, baseline disease activity, and week 10 remission status. All participants and study site personnel were masked to treatment assignment. The primary endpoint was remission at week 62 (MCS ≤2, with individual subscores ≤1, and rectal bleeding subscore of 0) among patients with a clinical response at week 10, measured in the modified intention-to-treat population (all randomised patients who received at least one dose of study drug). This trial is registered with ClinicalTrials.gov, NCT02165215, and is now closed to recruitment.

FINDINGS

Between Aug 12, 2014, and June 4, 2020, 658 patients were screened for eligibility and 359 were enrolled into the induction phase. 214 (60%) patients had a clinical response at week 10 and were randomly assigned to receive etrolizumab (n=108) or placebo (n=106) in the maintenance phase. 80 (74%) patients in the etrolizumab group and 42 (40%) in the placebo group completed the study through week 62. Four patients in the placebo group did not receive study treatment and were excluded from the analyses. At week 62, 32 (29·6%) of 108 patients in the etrolizumab group and 21 (20·6%) of 102 in the placebo group were in remission (adjusted treatment difference 7·7% [95% CI -4·2 to 19·2]; p=0·19). A greater proportion of patients reported one or more adverse events in the placebo group (82 [80%] of 102) than in the etrolizumab group (70 [65%] of 108); the most common adverse event in both groups was ulcerative colitis (16 [15%] patients in the etrolizumab group and 37 [36%] in the placebo group). Ten (9%) patients in the etrolizumab group and eight (8%) in the placebo group reported one or more serious adverse events. No deaths were reported in either treatment group.

INTERPRETATION

No significant differences were observed between maintenance etrolizumab and placebo in the primary endpoint of remission at week 62 among patients who had a clinical response at week 10. Etrolizumab was well tolerated in this population and no new safety signals were identified.

FUNDING

F Hoffmann-La Roche.

A pilot study to investigate the effect of topical microporous polysaccharide haemospheres on outcomes following robot-assisted radical prostatectomy

INTRODUCTION

Controlling bleeding without disturbing the anatomy and function of the structures in the prostate bed remains a significant challenge during radical prostatectomy (RP).

MATERIALS AND METHODS

Five grams of powdered microporous polysaccharide haemospheres (MPH) was applied to the prostate bed at the end of robot-assisted RP in 422 consecutive patients. Continence was defined as no pads and potency as the ability to have penetrative sex with or without PDE5 inhibitors in previously potent, non-diabetic men aged <70 years following bilateral intra- or inter-fascial neurovascular bundle (NVB) preservation.

RESULTS

In total, 95.3% of patients had nerve preservation and the mean operating time and blood loss were 142 minutes and 200ml, respectively. There were no intraoperative complications, and the postoperative transfusion rate was 0.2%. The mean hospital stay was 1.7 nights, and duration of catheterisation was 12 days. Final pathology demonstrated a mean prostate weight of 40.0g and 14.5% replacement by cancer, most commonly Gleason 7. The positive surgical margin rate for pT2 tumours was 10.0%. Biochemical recurrence was 2.1% at a mean follow-up of 18.0 months. Continence and potency rates at 4 weeks and 1 year after surgery were 76.4% and 97.7% and 27.8% and 78.1%, respectively. The trifecta and pentafecta rates 1 year after surgery were 53.1% and 45.8%.

DISCUSSION AND CONCLUSION

Powdered MPH applied to the prostate bed at the end of robot-assisted RP appears to be a safe, easily applied and useful adjunct to conventional haemostasis. The suggestion that it might also improve the functional outcomes of RP merits further investigation in the context of a randomised trial.

Robot-assisted salvage seminal vesicle excision for isolated recurrence after low-dose-rate prostate brachytherapy

OBJECTIVES

To report clinical and functional outcomes for patients who have undergone salvage robot-assisted seminal vesicle excision (RA-SVE) for the focal treatment of isolated seminal vesical (SV) recurrence after treatment for prostate cancer by low-dose-rate brachytherapy.

PATIENTS AND METHODS

Patients with rising prostate-specific antigen (PSA) after low-dose-rate prostate brachytherapy (LDR-PB) underwent multi-parametric magnetic resonance imaging (mp-MRI) of the prostate and ¹¹ C-Choline or ⁶⁸ Ga-prostate-specific membrane antigen (⁶⁸ Ga-PSMA) positron emission tomography/computed tomography (PET/CT) scan, followed by targeted transperineal biopsy of the prostate and SVs. Isolated SV recurrence were identified in 17 (0.38%) LDR-PB patients. These 17 patients were offered RA-SVE.

RESULTS

The median total operative time was 90 min and blood loss 50 mL with no postoperative transfusions required. The median hospital stay was 1 day. No intra- or postoperative complications were documented. Continence status was unaffected, no patient required urinary pads. Postoperative pathology confirmed SV invasion in all specimens. Surgical margins were positive in seven (41%) patients. All patients had at least one positive imaging study, although three (18%) mp-MRI and five (29%) PET/CT assessments were negative. One (6%) pre-SVE biopsy was also negative but with positive imaging. Salvage SVE failure, defined as three consecutive PSA rises or the need for further treatment, occurred in six patients of whom three had a positive margin. Overall failure-free survival rates were 86%, 67%, and 53% at 1, 2, and 3 years after SVE, respectively.

CONCLUSIONS

Salvage RA-SVE appears to be a safe focal treatment, with very low morbidity, for patients with localised SV recurrence after LDR-PB. It permits deferral of androgen deprivation therapy in selected patients. Bilateral SVE is mandatory. This surgical option should be considered in patients with isolated prostate cancer recurrence to the SV.

Can Tumour Volume Percentage in Radical Prostatectomy Predict Cancer Biochemical Recurrence? Determining a Cut-off Point and Composite Risk Factors Approach

BACKGROUND

Incidence of biochemical recurrence (BCR) after radical prostatectomy is relatively high and overall survival can be poor. Debate exists whether tumour volume predicts BCR and when treatments should be administered. In this study, we aimed to i) assess the impact of tumour volume percentage (TVP) as a predictor for BCR, ii) determine TVP cut-off point for BCR and iii) evaluate single and composite predictors of BCR.

METHODS

From March 2000 to December 2013, 1777 patients underwent laparoscopic radical prostatectomy for localized prostate cancer. None received neoadjuvant or adjuvant therapy. One hundred and forty-six patients experienced BCR (range 3 months-10 years). Using D'Amico classification, 146 matched controls without BCR were compared. Liu cut-point analysis was used to identify TVP with optimal sensitivity and specificity. Single and composite BCR risk predictors were analyzed using Cox hazards regression in cases and controls.

RESULTS

Median TVP was 10% (range 1-90%). Most of BCR peaked after 3 years of follow-up. TVP ≥8% was an independent predictor of BCR with HR 1.6 (p= 0.001, 95% CI= 1.11-2.48). TVP of 8% was associated with the highest accuracy: sensitivity 74% and specificity 53% (ROC curve= 0.7). At TVP ≥8%, pathological stage pT3 was associated with 1.7-fold higher risk of BCR compared to T2. Lymph node invasion was associated with 1.4-fold higher risk of BCR compared to no invasion. Combining TVP ≥8%, pT3 and lymph node invasion, HR jumped to 3.73 (p< 0.001, 95% CI= 2.27-6.14), whereas combining TVP ≥8%, positive surgical margin and lymph node invasion, HR was 2.68 (p= 001, 95% CI= 1.50-4.77).

CONCLUSION

TVP can be used as an independent predictor of BCR after radical prostatectomy for prostate cancer. TVP cut-point of ≥8% allows the best discrimination. TVP should be considered in combination with other clinico-pathological factors to improve prediction of long-term oncological outcomes and to stratify BCR risk.

Retzius-sparing robot-assisted radical prostatectomy: early learning curve experience in three continents

OBJECTIVE

To assess the effect of surgical experience on peri-operative, functional and oncological outcomes during the first 50 Retzius-sparing robot-assisted radical prostatectomy (RsRARP) cases performed by surgeons naïve to this novel approach.

MATERIALS AND METHODS

We retrospectively evaluated the initial cases operated by 14 surgeons in 12 different international centres. Pre-, peri- and postoperative features of the first 50 patients operated by each surgeon in all the participating centres were collected. The effect of surgical experience on peri-operative, functional and oncological outcomes was firstly evaluated after stratification by level of surgical experience (initial [≤25 cases] and expert [>25 cases]) and after using locally weighted scatterplot smoothing to graphically explore the relationship between surgical experience and the outcomes of interest.

RESULTS

We evaluated 626 patients. The median follow-up was 13 months in the initial group and 9 months in the expert group (P = 0.002). Preoperative features overlapped between the two groups. Shorter console time (140 vs 120 min; P = 0.001) and a trend towards lower complications rates (13 vs 5.5%; P = 0.038) were observed in the expert group. The relationship between surgical experience and console time, immediate urinary continence recovery and Clavien-Dindo grade ≥2 complications was linear, without reaching a plateau, after 50 cases. Conversely, a non-linear relationship was observed between surgical experience and positive surgical margins (PSMs).

CONCLUSIONS

In this first report of a multicentre experience of RsRARP during the learning curve, we found that console time, immediate urinary continence recovery and postoperative complications are optimal from the beginning and further quickly improve during the learning process, while PSM rates did not clearly improve over the first 50 cases.

Does Prostate HistoScanning™ accurately identify prostate cancer, measure tumour volume and assess pathological stage prior to radical prostatectomy?

Objective

The objective of this paper is to assess the ability of Prostate HistoScanning™ (PHS) to accurately identify tumour volume, index lesion characteristics and pathological stage. PHS is a novel technology employing transrectal ultrasound scanning and software analysis of radiofrequency data to produce signatures for benign and cancerous tissues. Recent reports have suggested PHS is capable of characterising the index cancer lesion and disease multifocality and detecting extraprostatic extension (EPE).

Materials and methods

The index test was preoperative PHS on patients undergoing radical prostatectomy (RP). The reference test was the whole-mount pathological analysis of the RP specimen. PHS analysis estimated total tumour volumes, tumour volumes by prostate sextant, the locations and volumes of index lesions, and the presence and location of EPE.

Results

There was no correlation between PHS and histology total tumour volume estimates (Pearson coefficient –0.099), despite accounting for specimen fixation shrinkage (Pearson coefficient –0.070), nor among 144 prostate sextants in 24 patients (Pearson coefficient 0.14). Sensitivity and specificity of PHS in detecting foci > 0.2 ml were 63% and 53%, respectively; and 37% and 71%, respectively, for foci > 0.5 ml. Pearson correlation coefficient for index lesion volumes identified at pathology vs PHS was 0.065. PHS failed to locate accurately index lesion and pathological EPE.

Conclusions

PHS fails to identify total tumour volumes, tumour volumes prostate sextant, index lesion volumes and locations, and presence and location of EPE compared to RP pathology. PHS appears unsuitable for routine diagnostic clinical use in prostate cancer.

An in vivo screen identifies ependymoma oncogenes and tumor-suppressor genes

Cancers are characterized by non-random chromosome copy number alterations that presumably contain oncogenes and tumor-suppressor genes (TSGs). The affected loci are often large, making it difficult to pinpoint which genes are driving the cancer. Here we report a cross-species in vivo screen of 84 candidate oncogenes and 39 candidate TSGs, located within 28 recurrent chromosomal alterations in ependymoma. Through a series of mouse models, we validate eight new ependymoma oncogenes and ten new ependymoma TSGs that converge on a small number of cell functions, including vesicle trafficking, DNA modification and cholesterol biosynthesis, identifying these as potential new therapeutic targets.

Acceptability of drug detection monitoring among participants in an open-label pre-exposure prophylaxis study

In the world of HIV pre-exposure prophylaxis (PrEP) research, there is emerging interest in providing study participants with pharmacokinetic results from drug level testing to guide adherence counseling. The iPrEx randomized control trial was the first study to produce meaningful results of PrEP in humans. In the iPrEx open-label extension (OLE) study, blood plasma samples collected in the first 12 weeks of study participation were tested for the presence of tenofovir/emtricitabine--the drugs which compromise PrEP. Study clinicians shared results (detectable/undetectable) with participants at their 24-week visit. We evaluated the acceptability of receiving these results among a subset of iPrEx OLE participants. We conducted in-depth interviews (n = 59) with participants (those with and those without drug detected) enrolled in Boston, Chicago, and San Francisco to assess their experiences with receiving drug detection feedback. Incorporating drug detection results into the clinical study visit was well received and no negative reactions were expressed. For about half of participants, receiving their drug detection lab result was useful while for others it was not important. In a few cases, no drug detected results led to increased efforts to take PrEP consistently and in most cases enhanced open discussion of missed doses. Participants reported a desire for greater specificity, particularly quantitative drug levels needed for protection. We recommend exploring strategies to increase the salience of drug level results, including using feedback to target adherence counseling, and reducing the time between specimen collection, testing, and receipt of results. Future studies should evaluate the feasibility and impact of providing more specific quantitative drug levels using biomarkers of longer term PrEP exposure, i.e., hair/dried blood spots.

HIV-1 drug resistance in the iPrEx preexposure prophylaxis trial

BACKGROUND

The iPrEx study demonstrated that combination oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) as preexposure prophylaxis (PrEP) protects against HIV acquisition in men who have sex with men and transgender women. Selection for drug resistance could offset PrEP benefits.

METHODS

Phenotypic and genotypic clinical resistance assays characterized major drug resistant mutations. Minor variants with FTC/TDF mutations K65R, K70E, M184V/I were measured using 454 deep sequencing and a novel allele-specific polymerase chain reaction (AS-PCR) diagnostic tolerant to sequence heterogeneity.

RESULTS

Control of primer-binding site heterogeneity resulted in improved accuracy of minor variant measurements by AS-PCR. Of the 48 on-study infections randomized to FTC/TDF, none showed FTC/TDF mutations by clinical assays despite detectable drug levels in 8 participants. Two randomized to FTC/TDF had minor variant M184I detected at 0.53% by AS-PCR or 0.75% by deep sequencing, only 1 of which had low but detectable drug levels. Among those with acute infection at randomization to FTC/TDF, M184V or I mutations that were predominant at seroconversion waned to background levels within 24 weeks after discontinuing drug.

CONCLUSIONS

Drug resistance was rare in iPrEx on-study FTC/TDF-randomized seroconverters, and only as low-frequency minor variants. FTC resistance among those initiating PrEP with acute infection waned rapidly after drug discontinuation. Clinical Trials Registration.NCT00458393.

Does prostate HistoScanning™ play a role in detecting prostate cancer in routine clinical practice? Results from three independent studies

OBJECTIVES

To evaluate the ability of prostate HistoScanning™ (PHS; Advanced Medical Diagnostics, Waterloo, Belgium) to detect, characterize and locally stage prostate cancer, by comparing it with transrectal ultrasonography (TRUS)-guided prostate biopsies, transperineal template prostate biopsies (TTBs) and whole-mount radical prostatectomy specimens.

SUBJECTS AND METHODS

Study 1. We recruited 24 patients awaiting standard 12-core TRUS-guided biopsies of the prostate to undergo PHS immediately beforehand. We compared PHS with the TRUS-guided biopsy results in terms of their ability to detect cancer within the whole prostate and to localize it to the correct side and to the correct region of the prostate. Lesions that were suspicious on PHS were biopsied separately. Study 2. We recruited 57 patients awaiting TTB to have PHS beforehand. We compared PHS with the TTB pathology results in terms of their ability to detect prostate cancer within the whole gland and to localize it to the correct side and to the correct sextant of the prostate. Study 3. We recruited 24 patients awaiting radical prostatectomy for localized prostate cancer to undergo preoperative PHS. We compared PHS with standardized pathological analysis of the whole-mount prostatectomy specimens in terms of their measurement of total tumour volume within the prostate, tumour volume within prostate sextants and volume of index lesions identified by PHS.

RESULTS

The PHS-targeted biopsies had an overall cancer detection rate of 38.1%, compared with 62.5% with standard TRUS-guided biopsies. The sensitivity and specificity of PHS for localizing tumour to the correct prostate sextant, compared with standard TRUS-guided biopsies, were 100 and 5.9%, respectively. The PHS-targeted biopsies had an overall cancer detection rate of 13.4% compared with 54.4% for standard TTB. PHS had a sensitivity and specificity for cancer detection in the posterior gland of 100 and 13%, respectively, and for the anterior gland, 6 and 82%, respectively. We found no correlation between total tumour volume estimates from PHS and radical prostatectomy pathology (Pearson correlation coefficient -0.096). Sensitivity and specificity of PHS for detecting tumour foci ≥0.2 mL in volume were 63 and 53%.

CONCLUSIONS

These three independent studies in 105 patients suggest that PHS does not reliably identify and characterize prostate cancer in the routine clinical setting.

Robot-assisted and laparoscopic repair of ureteropelvic junction obstruction: a systematic review and meta-analysis

CONTEXT

Over the last two decades, minimally invasive treatment options for ureteropelvic junction obstruction (UPJO) have been developed and popularized.

OBJECTIVE

To critically analyze the current status of laparoscopic and robotic repair of UPJO.

EVIDENCE ACQUISITION

A systematic literature review was performed in November 2012 using PubMed. Article selection proceeded according to the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria.

EVIDENCE SYNTHESIS

Multiple series of laparoscopic pyeloplasty have demonstrated high success rates and low perioperative morbidity in pediatric and adult populations, with both the transperitoneal and retroperitoneal approaches. Data on pediatric robot-assisted pyeloplasty are increasingly becoming available. A larger number of cases have also been reported for adult patients, confirming that robotic pyeloplasty represents a viable option for either primary or secondary repair. Robot-assisted redo pyeloplasty has been mostly described in the pediatric population. Different technical variations have been implemented with the aim of tailoring the procedure to each specific case. The type of stenting, retrograde versus antegrade, continues to be debated. Internal-external stenting as well as a stentless approach have been used, especially in the pediatric population. Comparative studies demonstrate similar success and complication rates between minimally invasive and open pyeloplasty in both the adult and pediatric setting. A clear advantage in terms of hospital stay for minimally invasive over open pyeloplasty was observed only in the adult population.

CONCLUSIONS

Laparoscopy represents an efficient and effective less invasive alternative to open pyeloplasty. Robotic pyeloplasty is likely to emerge as the new minimally invasive standard of care whenever robotic technology is available because its precise suturing and shorter learning curve represent unique attractive features. For both laparoscopy and robotics, the technique can be tailored to the specific case according to intraoperative findings and personal surgical experience.

Abstract 3448: Subtypes of medulloblastoma have distinct developmental origins

Medulloblastoma encompasses a collection of clinically and molecularly diverse tumor subtypes that together comprise the most common malignant childhood brain tumor. These tumors are thought to arise within the cerebellum, with approximately 25% originating from granule neuron precursor cells (GNPCs) following aberrant activation of the Sonic Hedgehog pathway (hereafter, SHH-subtype). The pathological processes that drive heterogeneity among the other medulloblastoma subtypes are not known, hindering the development of much needed new therapies. Here, we provide evidence that a discrete subtype of medulloblastoma that contains activating mutations in the WNT pathway effector CTNNB1 (hereafter, WNT-subtype), arises outside the cerebellum from cells of the lower rhombic lip (LRL). We found that genes marking human WNT-subtype medulloblastomas are more frequently expressed in the LRL and embryonic dorsal brainstem than in the upper rhombic lip (URL) and developing cerebellum. Magnetic resonance imaging (MRI) and intra-operative reports showed that human WNT-subtype tumors infiltrate the dorsal brainstem, while SHH-subtype tumors are located within the cerebellar hemispheres. Activating mutations in Ctnnb1 had little impact on progenitor cell populations in the cerebellum, but caused an aberrant accumulation of proliferating precursor cells within the LRL. These lesions persisted in the dorsal brainstem of all mutant adult mice and in 15% of cases in which Tp53 was concurrently deleted, progressed to form medulloblastomas that modeled faithfully the anatomy and gene expression profiles of human WNT-subtype medulloblastoma. We provide the first evidence that subtypes of medulloblastoma have distinct cellular origins. Our data provide an explanation for the marked molecular and clinical differences between SHH and WNT-subtype medulloblastomas and have profound implications for future research and treatment of this important childhood cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3448. doi:10.1158/1538-7445.AM2011-3448

Subtypes of medulloblastoma have distinct developmental origins

Medulloblastoma encompasses a collection of clinically and molecularly diverse tumor subtypes that together comprise the most common malignant childhood brain tumor1–4. These tumors are thought to arise within the cerebellum, with approximately 25% originating from granule neuron precursor cells (GNPCs) following aberrant activation of the Sonic Hedgehog pathway (hereafter, SHH-subtype)3–8. The pathological processes that drive heterogeneity among the other medulloblastoma subtypes are not known, hindering the development of much needed new therapies. Here, we provide evidence that a discrete subtype of medulloblastoma that contains activating mutations in the WNT pathway effector CTNNB1 (hereafter, WNT-subtype)1,3,4, arises outside the cerebellum from cells of the dorsal brainstem. We found that genes marking human WNT-subtype medulloblastomas are more frequently expressed in the lower rhombic lip (LRL) and embryonic dorsal brainstem than in the upper rhombic lip (URL) and developing cerebellum. Magnetic resonance imaging (MRI) and intra-operative reports showed that human WNT-subtype tumors infiltrate the dorsal brainstem, while SHH-subtype tumors are located within the cerebellar hemispheres. Activating mutations in Ctnnb1 had little impact on progenitor cell populations in the cerebellum, but caused the abnormal accumulation of cells on the embryonic dorsal brainstem that included aberrantly proliferating Zic1⁺ precursor cells. These lesions persisted in all mutant adult mice and in 15% of cases in which Tp53 was concurrently deleted, progressed to form medulloblastomas that recapitulated the anatomy and gene expression profiles of human WNT-subtype medulloblastoma. We provide the first evidence that subtypes of medulloblastoma have distinct cellular origins. Our data provide an explanation for the marked molecular and clinical differences between SHH and WNT-subtype medulloblastomas and have profound implications for future research and treatment of this important childhood cancer.

The learning curve for laparoscopic radical prostatectomy: an international multicenter study

PURPOSE

It is not yet possible to estimate the number of cases required for a beginner to become expert in laparoscopic radical prostatectomy. We estimated the learning curve of laparoscopic radical prostatectomy for positive surgical margins compared to a published learning curve for open radical prostatectomy.

MATERIALS AND METHODS

We reviewed records from 8,544 consecutive patients with prostate cancer treated laparoscopically by 51 surgeons at 14 academic institutions in Europe and the United States. The probability of a positive surgical margin was calculated as a function of surgeon experience with adjustment for pathological stage, Gleason score and prostate specific antigen. A second model incorporated prior experience with open radical prostatectomy and surgeon generation.

RESULTS

Positive surgical margins occurred in 1,862 patients (22%). There was an apparent improvement in surgical margin rates up to a plateau at 200 to 250 surgeries. Changes in margin rates once this plateau was reached were relatively minimal relative to the CIs. The absolute risk difference for 10 vs 250 prior surgeries was 4.8% (95% CI 1.5, 8.5). Neither surgeon generation nor prior open radical prostatectomy experience was statistically significant when added to the model. The rate of decrease in positive surgical margins was more rapid in the open vs laparoscopic learning curve.

CONCLUSIONS

The learning curve for surgical margins after laparoscopic radical prostatectomy plateaus at approximately 200 to 250 cases. Prior open experience and surgeon generation do not improve the margin rate, suggesting that the rate is primarily a function of specifically laparoscopic training and experience.

Cross-species genomics matches driver mutations and cell compartments to model ependymoma

Understanding the biology that underlies histologically similar but molecularly distinct subgroups of cancer has proven difficult because their defining genetic alterations are often numerous, and the cellular origins of most cancers remain unknown. We sought to decipher this heterogeneity by integrating matched genetic alterations and candidate cells of origin to generate accurate disease models. First, we identified subgroups of human ependymoma, a form of neural tumour that arises throughout the central nervous system (CNS). Subgroup-specific alterations included amplifications and homozygous deletions of genes not yet implicated in ependymoma. To select cellular compartments most likely to give rise to subgroups of ependymoma, we matched the transcriptomes of human tumours to those of mouse neural stem cells (NSCs), isolated from different regions of the CNS at different developmental stages, with an intact or deleted Ink4a/Arf locus (that encodes Cdkn2a and b). The transcriptome of human supratentorial ependymomas with amplified EPHB2 and deleted INK4A/ARF matched only that of embryonic cerebral Ink4a/Arf(-/-) NSCs. Notably, activation of Ephb2 signalling in these, but not other, NSCs generated the first mouse model of ependymoma, which is highly penetrant and accurately models the histology and transcriptome of one subgroup of human supratentorial tumour. Further, comparative analysis of matched mouse and human tumours revealed selective deregulation in the expression and copy number of genes that control synaptogenesis, pinpointing disruption of this pathway as a critical event in the production of this ependymoma subgroup. Our data demonstrate the power of cross-species genomics to meticulously match subgroup-specific driver mutations with cellular compartments to model and interrogate cancer subgroups.